The Russian aviation industry has a terrible track record on delivering new aircraft.
Their own press photos shows uncovered Philips screws on a supposedly stealth aircraft, and their "loyal wingman" drone used the first opportunity near the frontlines to try to defect.
But there remains a question of quantity and determination.
I'm not sure how applicable this would be to a confrontation with European countries. Russian fighters will get getting lots of flight hours on CAP as well, but not much combat based on reporting. Both sides are keeping everything inside their own AD bubbles.